Sparkproof flooring



July 6, 1943. w, w, DONELSON 2,323,461

SPARKPROOF FLOORING Filed OC.. 5.50,` 1941 v @nl /4 sa ggf Patented July 6,1943l UNITED STATES PATENT oFF-.ICE

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William Warren Donelson, Boston, Mass., signor to The Federal Flooring Corporation, Boston, Mass., a-corporation of Massachusetts Application october so, 1941, serial No. 417,144 s claims- (ci. 11s-264) characteristics.

Sparkproof flooring is employed for industrial purposes which require very extensive floor i areas and the cost of production, in both mate-v ria-l and labor, 'is therefore of prime importance. I have discovered that great economy in the production of such flooring is secured by employing a relatively thin -layer of conductive material, such as conductive rubber cementv or paste, on the sub-floor and placing thereon a top iloor together with conductive studsin contact with the conductive material and so spaced and exposed at'the top surfaceof the flooring that objects resting on or moving over the flooring come in contact therewith and thereby have static charges immediately dissipated therefrom. The conductive studs can be placed adhesively on the conductive material and plastic flooring composition spread vthereover in a manner exposing the studs at the top flooring surpastes.

crete. In accordance with my invention I ren' der the top surface of the lsub-floor electrically conductive by placing a thin layer of conductive material thereover at 12. The material which I prefer to employ is conductive rubber and this can be applied like apaint with a, brush or as a paste with a trowel to provide a coating M" to 1750 thick, although a thin pre-fabricated sheet of conductive material can be employed if desired. Other conductive materials which-will serve the purpose can be used, suchas a conductive asphalt paste or conductive gum These conductive liquids or pastes can be :formed by adding a conductive liller, as graphite, carbon or powdered coke. tov a base of liquid rubber, asphalt or gums, together with a suitable solvent. The coating willy preferably 'bev of an adhesive nature whereby to adhere to con` iiooringis then finished by applying a. top iiooring yIB of plastic composition on and over the kcoating l2. 'I'his composition can be of mag-.-

nesite, asphalt or other suitable'material which will take wear and not spark from impact. The conductive coating I2 is preferably grounded at several locations Il suitably spaced to facilitate face, or the studs can be previously. placed within prepared top flooring, such as rubber, linoleum, tiling, etc., and the combined top flooring and studs thereafter placed onto the layer of conductive material, all'as hereinafter more specifically described; The production of a novel sparkproof flooring of this nature comprises a shown in the accompanying Vdrawing wherein:-

Fig. 1 is a fragmentary view of a flooring constructed in accordance with one embodiment of the invention, portions thereof -being broken away to illustrate the process of construction, e Fig. 2 is a like view of afmodified construction,

Figs. 3- and 4 illustrate' modifications of the Y construction shown in Fig. 2.

Referring first to Fig. l of the drawing, IIindicates the sub-floor which is preferably of conf dissipation of static chargesl It may in some cases be desirable to employ pre-fabricated' top flooring such as rubber ooring.. linoleum, asphalt, tile. etc., all of which are sparkproof from impact, and my invention is well adapted thereto. In such casethe coni Aductive coating `22 is applied to the sub-floor 20,

as above described, and the previously prepared e top flooring 2B is laid thereonto. 'Ihe top floor- V ing can be conveniently prepared in the shop by perforating the flooring and inserting studs or disks 24 frictionally within theperforations. The disks are exposed at and substantially flush with both faces of the flooring so that the bottom face will contact with the conductive layer 22 and the top face will be exposed when the top flooring is laid in place. The conductive coatwithin the top ooring 26 lis most simple and convenient, it is possible t o\mount them more permanently if desired. For example in Fig. (i the studs Il are illustrated as having centrally located hns Il whereby the rubber or asphalt ilooring il can be molded in holding relation onto the studs. The conductive layer l2 is applied to the sub-floor 30 in the manner above described and is grounded at 38. In Fig. 4 is illustrated a-stud u which has been riveted into the iiooring I0 of the linoleum or the like. `Either or both vencis oi the rivet body can be upset over the flooring and the overlapping top portion will preferably be somewhat thicker to provide a suitable wearing surface. Y The conductive layer on the sub-hoor 40 is indicated at 4,2 and is grounded at I8.

The application and advantages of my improved sparkproof ooring will be readily apparent. The studs, which can be of any suitable conductive material. as brass, copper, bronze, conductive' rubber, etc., are spaced suiliciently close to be contacted by objects resting on or moving over the iioor and function directly to dissipate static charges therefrom with a minimum oi resistance. Furthermore, the top nooring and studs are of materials which will not spark on impact, the flooring therefore beingsparkproot from both impact and static sources.

The relative simplicity and economy oi this -claim as new and desire to secure by Letters Patent of the United States is:

1. Sparkproof flooring comprising a sub-door.

- a thin layer of conductive material on and covering the sub-floor, a top flooring on and covering the conductivel material, and conductive ,studs extending through the top iloor and in contact with the conductive material, the studs being in a predetermined and relatively close relationship and their top surfaces being substantially flush with the topl surface of the flooring. 2. Sparkproof ooringcomprising a subiloor.

a thin layer of conductive material on and covering the sub-diner, a top oor in face to face bonded contact with and covering said layer, and studs of conductive non-ferrous metal extending through the top iloor and in contact with the conductive layer, the studs being in a predetermined and relatively close relationship and their top surfaces being exposed at the top surface of the ilooring.

3. A prefabricated sparkproof top flooring, comprising a relatively thin sheet of exible flooring' material, and electro-conductive studs in predetermined and relatively close relationship therein. the studs being exposed at and substantially ilush with both faces of the sheet and the flooring being adapted for use with a grounded conductor located therebeneath and in contact with the studs.

-r WILLIAM WARREN DONELSON. 

